Electrical insulation



ELECTRICAL INSULATION,-

Filed Jan. 6, 1935 INSULATION COMPRISING COPPER HALIDE CONDUCTOR Inventor: Robert H. Muller,

His Attorney.

Patented July 7, 1936 ELECTRICAL INSULATION Robert H. Miller, Berlin, Germany, assignor to General Electric Company, a. corporation of New York Application January 6, 1933, Serial No. 650,382 In Germany January 12, 1932 1 Claim. (Cl. 173-264) The present invention relates to electrical insulation and more particularly to inorganically insulated electrical conductors.

' It'is often desirable to insulate copper con- 5 ductors with coatings which withstand temperatures up to 200 or 300 C. Organic varnish coatings are not suflicient for this purpose. The well known insulations with aluminum oxide or zinc combinations offer great difliculty in their 10 production on copper conductors. Further they are ordinarily porous and therefore usually guarantee no protection against moisture.

According to the invention these difliculties can be avoided if the insulating coating on the 15 copper conductor is produced directly from copper combinations. It has been shown that copper halide and its complex combinations, 6. g. cuprous, chloride or cuprousv bromide are suitable for this purpose. They are produced either on the copper conductor or are placed on it as combinations and then fused, or are applied on the conductor in a fused state.

The accompanying drawing illustrates in cross- 7 section a conductor insulated with insulation 25 comprising copper halide.

The production can be carried out in a known manner by electrolysis. The copper conductor is wired as anode in a bath which contains the halogen ion. It may be convenient to add acids, 3 e. g. phosphoric acid, or salts of acids, of which the decomposition voltage lies'above the decomposition voltage of the corresponding halogen combinations, in order to keep the hydrogen ion concentration within the limits necessary for un-' 35 disturbed procedure of the reaction.

When the fused simple or complex copper halide is used, a little copper is added to the melt, to preventbxidation. To this end the melt container may be manufactured of copper or other copper plated material. The layer manufactured in accordance with the invention forms a glassy coating which is absolutely impervious. It is also possible to add filling materials such as asbestos to the insulating layer, and, for example, the deposited material 10 which is at first porous can be mixed with asbestos and fused to a homogeneous substance at a higher temperature. Filling materials such as quartz meal, mica powder and so on can be scattered on the porous layer of insulation before heat treatment and then fusing can be done. Further, there is the possibility of placing asbestos covered wires in an electrolysis bath, producing the insulating precipitates between the covering and the conductor and fusing to a substance with the asbestos by means of suitable temperature treatment. The conductor can also be exposed to the action of free halogen, e. g. in a heated gas containing nalogen or by drawing the heated conductor through a cold halogen atmosphere.

What I claim as new and desire to secure by Letters Patent of the United States is:

A copper conductor insulated with inorganic insulation consisting of an impervious glass-like coating of copper halide containing'homogeneously distributed therein a fused mineral filler containing silica.

4 R. H. MULLER. 

